The present invention relates to a gate driver for power semiconductor devices.
Many low voltage electronic circuits, e.g., MOSFET devices, are used to drive high voltage switching transistors, e.g., power MOSFETs, insulated gate bipolar transistor devices (IGBTs), gate controlled thyristors, and the like. A power semiconductor switch or device is switched from a nonconducting state to a conducting state by raising the gate-source voltage from below to above a threshold voltage.
One or more low voltage transistors, coupled to an output node of the gate driver, apply appropriate voltages to the gate or control terminal of the power device to turn on or turn off the power device. When the power device is an N-channel metal oxide semiconductor field effect transistor (NMOSFET), the device is turned on by applying a high voltage to the gate of the power switch and turned off by applying a low voltage to the gate. In contrast, if the power device is a P-channel metal oxide semiconductor field effect transistor (PMOSFET), the device is turned on by applying a low voltage to the gate of the power switch and turned off by applying a high voltage to the gate.
Circuitry of the gate driver may be configured a number of different ways. In one common configuration, the gate driver includes two transistors, i.e., upper and lower transistors, connected in series in a half bridge configuration. The upper transistor is a P-type transistor, such as a PMOSFET or PNP bipolar transistor. The lower transistor is an N-type transistor, such an NMOSFET or NPN bipolar transistor. An output node of the gate driver is coupled to a node between the two transistors to output and apply a high or low potential to the gate of the power switch according to the conductive states of the two transistors in series.